In the related art, there is a known technique in which correlations among a plurality of images are calculated and the images are combined by controlling, on the basis of the correlations, the ratios at which the images are combined (for example, see Patent Literature 1). In this technique, one of the plurality of captured images is used as a standard image, the other images are used as reference images, and correlations (differences) are calculated between the standard image and the reference images for individual regions therein; and the combining ratios of the reference images are controlled so as to be increased with an increase in the correlations, and the combining ratios of the reference images are controlled so as to be decreased (the ratio of the standard image is increased) with a decrease in the correlations.
Specifically, the regions having high correlations are determined to be regions in which positioning errors are low and correction processing is not performed therefor, and the regions having low correlations are determined to be regions having positioning errors and a high-resolution image is subjected to correction processing, such as filtering processing or the like, thus correcting irregular positioning-displacement artifacts.
On the other hand, in the case in which a high-resolution image is acquired by combining a plurality of low-resolution images, it is important to place information (pixels) in the plurality of low-resolution images at appropriate positions in an image space having a greater resolution than those of the low-resolution images, and it is not possible to achieve a resolution-enhancement effect when placement at the appropriate positions fails.